Electronic character selecting and/or printing apparatus



Sept- 24, 1957 c. J. YOUNG 2,807,663

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ELECTRONIC CHARACTER SELECTING AND/OR PRINTING APPARATUS Filed om. 2,1950 'r Sheets-Sheet 7 fi NEW V\\ W, OIL QQ United States PatentELECTRONIC CHARACTER SELECTING AND/ OR PRINTING APPARATUS Charles J.Young, Princeton, N. J., assignor to Radio Corporation of America, acorporation of Delaware Application October 2, 1950, Serial No. 187,87 9

4 Claims. (Cl. 178--15) The present invention relates to the selectionof indicia including readable characters, and, more particularly, butnot-necessarily exclusively, to novel means for selecting indicia, suchas letters of the alphabet and for arranging and presenting the selectedindicia in useable form. Selection, in accordance with the invention,may occur at a place which is remote from the place of arrangement andpresentation.

In accordance with the inveniton, an electronically produced letter ofthe alphabet, for example, is shifted, preferably by electronic means,to fit into an intelligible arrangement of similar letters. Initialproduction of the letter is obtained by a selective process. Codecontrol is employed for guiding the selection. The resultingintelligible arrangement of letters is recorded by photographic means,for example, or by other means. Suitable recording mediums may beemployed which are sensitive to visible or invisible radiant energy.Photographic methods of recording are responsive to visible as well asinvisible radiation and are, therefore, suitable. Radiation controlledelectrostatic patterns may be employed for recording. The invention, ineflect, provides type selection and type setting by electronicinstrumentalities.

An object of the invention is to provide for the selection of discreteindicia and to arrange the selected indicia in intelligible form.

Another object is to provide novel means for scanning the electron beamsensitive area of a cathode ray tube.

A further object is to provide novel means for controlling scanningdeflection of the electron beam in a cathode ray tube.

A still further object is to provide novel means for the electronicselection of indicia by code controlled means.

Other objects and advantages of the invention will, of course, becomeapparent and immediately suggest themselves to those skilled in the artto which the invention is directed from a reading of the followingspecification in connection with the accompanying drawings in which:

Fig. 1 is a schematic showing of a transmitter suitable for derivingcode signals representing letters of the alphabet-or other indicia;

Fig. 2 shows a fragment of transparent tape marked with code characters;

Fig. 3 is a schematic showing of apparatus for selecting and arrangingcharacters or other indicia when provided with coded signals;

Figs. 4a to 4 show a series of waveforms used in explaining theoperation of the apparatus of Fig. 3;

Fig. 5 and 5a are to be combined as a schematic diagram of one of theprincipal units shown by Fig. 3;

Figs. 6 and 7 disclose details of arrangements in accordance with theinvention for controlling functions of the apparatus;

Fig. 8 is similar to Fig. 3 and shows another embodiment of theinvention;

Fig. 9 is a view of the character defining means of the inventionrepresenting characters disposed for selection;

Fig. 10 is a view illustrating selected characters arranged inintelligible order, only one of which would be visible in practice ofthe invention in a preferred form; and

Fig. 11 is a schematic showing of apparatus, similar to the apparatus ofFig. 8, for selecting and arranging of Fig. 1 may, if desired, includefeatures shown in' Zworykin Patent No. 1,753,961, granted April 8, 1930.A patent to Cremer No. 1,828,556, dated Oct. 20, 1931, also discloses acode transmitter suitable for purposes of carrying out this invention.Fig. 2 of the drawing shows a fragment of a strip of tape bearing codecharacters rep resenting the word now.

The receiving and recordingarrangement of Fig. 3 includes two flyingspot cathode ray tube scanners or kine scopes 12 and 14. The principleof the flying spot scanner is shown in Patent No. 2,104,066 granted toV. K.

Zworykin on Jan. 4, 1938. A slide or mask 16 is interposed between theflying spot tube scanner 12 and a phototube 18. An amplifier 20 isprovided for the phototube output. The slide 16 may, if desired, be inthe form of a mask applied directly to the face of the kinescope 12. Theindicia may be opaque or transparent on an opaque field. Fig. 9 of thedrawing shows the slide or mask 16 somewhat in detail. It is dividedinto squares which correspond to components of deflection superim--posed on the raster deflection means of the kinescope;

For example, the square inscribed with the letter e is reached bydeflecting the beam three units horizontally and five units verticallyfrom the upper left-hand or rest position. normally maintain the beam inthe rest position, and

steady deflection components to select a square on the mask 16 varythese readily applied deflection components.

Alternatively, and more simply, the well-known gun structure of thekinescope 12 may be located so as to direct the beam to the portion ofthe screen occupied by the square representing the rest position in theabsence of coordinate deflection voltages or currents. A deflection yokeis indicated by reference character 21. This yoke may be of the kindfully described in Patent No. 2,428,947 granted to C. E. Torsch on Oct.14, 1947. The coordinate deflection currents may be superimposed on thewindings of the yoke 21 or an auxiliary yoke (not shown) may be providedwhich surrounds the yoke 21 or lies adjacent to it.

The electron beam of the cathode ray tube is deflected over a scanningpattern or raster, this raster having an area sutficient only to coverone of the squares of the mask 16. raster produced in a television tube,but it need not be interlaced. Scanning apparatus including vertical andhorizontal oscillators and vertical and horizontal discharge tubes is bynow well known. Reference character 24 indicates schematically a rastergenerator which may be of any well-known type. Deflection control circuits for a kinescope are shown in Patent No. 2,101,520 granted toTolson et al. on Dec. 7, 1937. The deflection timing, however, for theraster generator 24 is obtained in a novel manner later to be described.

The kinescope 14 is provided with a deflection yoke 26 which is or maybe similar to the yoke 21 described in connection with the kinescope 12.The yoke 26 receives deflection currents from the raster generator 24 soas to produce a scanning raster of nearly the size of the raster on thetube 12 on the target area or face of the kinescope.

Properly applied deflection currents or voltages The scanned raster maybe similar to the In addition, the yoke provides a component ofhorizontal deflection which is adjustable stripwise to shift thescanning pattern or raster horizontally on the tube face. It will beunderstood that the terms vertical and horizontal are used herein merelyto designate components of scanning and do not necessarily have anyrelationship to the position in space of the target face of thekinescopes 12 and 14. Fig. of the drawings shows diagrammatically theexposed screen or target face of the kinescope 14. The adjustable orvariable component of horizontal defiection in the illustrative view ofFig. 3 has been set so that the rectangular raster producing the lettere by modulation of the kinescope beam has been moved along the targetface of the tube so that this letter e occupies a position on the tubeto form a letter of an intel igibly arranged word. Reference numeral 29designates a sheet or web of radiant energy or light sensitive materialupon which light is projected from the target face on the kinescope 14by a lens 31. In the message example of Fig. 10, the line of lettersappearing on the screen of the kinescope 14 will be recorded on the web29. Following selection and presentation of a line of characters, theweb is moved through one line space which may be accomplished as shownillustratively by drawing the web over a driven roll 33. This may beaccomplished in the wellknown manner by a rachet mechanism actuated bythe paper advance control 34. The paper advance control 34 as well asthe other apparatus making up Fig. 3 will be described more in detailhereinafter.

From the foregoing general description of the arrangement of Fig. 3, itwill be seen that type characters are selected by the kinescope 12 andare in effect set by the kinescope 14.

As stated above, the apparatus of Fig. 3 is controlled by received codepulses. Referring to Fig. 2, there is shown a fragment of tape from amessage bearing strip. In Fig. 2, the tape 36 may be transparent andcode marks 38 thereon may be opaque. Fig. 1 of the drawings shows a tapetransmitter or reader having a tape 39 with code punchings 41 therein.For the sake of convenience of description, the tape 36 and the tape 39will be regarded as full equivalents, and it will be assumed that opaquetape with code punchings 41 is employed. -In accordance with theembodiment of the invention shown in Fig. 3 a six-unit code, devised aspart of the present invention, is used in which the intelligence pulses43 (Fig. 4a) are preceded by a start pulse 44. There are six positionsspaced laterally of the tape which may be occupied by punched holes 41.The code combination for w is in position to be read by three phototubesin the phototube bank 46. 'A suitable lamp 40 projects light throughlight guides 42 onto the phototubes. Lens means or other optical meansmay be employed to direct light from the lamp 40 through a given hole 41onto the corresponding phototube. The anode or output circuits of thephototubes are connected through an amplifier 48 having separateamplifying paths, to the contacts 49 of a rotary distributor. Thedistributor is shown, illustratively as a mechanical commutator,however, an optical or electronic distributor will be necessary to matchthe high operating speed capabilities of systems embodying thisinvention. One contact 51 provides the start pulse. This may be ofgreater amplitude than the intelligence pulses 43 to afford amplitudediscrimination for separation. The distributor output terminal 54 isavailable for connection to a transmission line or the input to a radiotransmitter. For use in counting or computing dvices, or the like, thetransmitter and receiver or printer will be located adjacent each other.

In Fig. 3, coded signals, such, for example, as the signals appearing atterminal 54 of Fig. l, are applied to the terminal 59 and are amplied byan amplifier 61 of known construction. One output connection 63 of theamplifier feeds a code converter 66 which is shown more in detail inFigs. 5 and 5a. The device 66 receives the groups of pulses identifyingthe letters and changes them into related values of deflection current,which are fixed momentarily for the time of one raster. Furthermore, analternate letter cycle is set up so that, while one letter is beingscanned, the code for the next letter is being converted. This allowsmaximum time for each function. To avoid unnecessary repetition in thedrawing, Figs. 5 and 5a show slightly more than one-half of the circuitsince the diagram can be symmetrical about the axis of the schematicallyshown kinescope 12.

The other output connection 67 of the amplifier 61 feeds a device 68which provides a series of pulses (Fig. 4d) designated 69. The device 68is in the form of a commutator circuit and in the illustrative examplehas 7 stages. A circuit suitable for the purpose is shown in Patent Re.22,672 granted to C. C. Shumard on Aug. 28, 1945. The preferredcommutator circuit does not have overall feedback so that it will count7 and stop until the next incoming start pulse 44 trips its first stage.A stable oscillator of any known type is indicated by referencecharacter 74 which provides pulses to be counted by the counter chaincircuit of the device 63. The oscillator 74 is preferably adjusted to aslightly faster rate than the incoming signal pulses 43 and 44. Tapsfrom the several stages are designated 81 to 87 which are connected topoints in the device 66 as shown by Figs. 5 and 5a of the drawing. Aslight phase adjustment of the sync pulses 69 derived from theoscillator in combination with the device 68 will permit centering thesync pulses on the best part of the received pulses 43. The receivedpulses may then be considerably degraded at start and finish allowingthese sync pulses to be transmitted over a relatively low qualitytransmission channel. The device 68 also supplies a triggering voltageover the connection 92 to the raster generator 24.

Multivibrators 102 to 107 in the code converter 66 (shown in detail inFig. 5) form a storage bank in which is set the code for one letter asit is received. Operation of the multivibrators determines which tubesof the bank of tubes 112 to 117 is conductive. Electronic apparatusemploying multivibrators similar to those shown illustratively in Fig. 5of the drawing are discussed in an article entitled Electronic DigitalCounters by Warren H. Bliss appearing in the April 194-9 issue ofElectrical Engineering. The tubes 112 to 117 are screen grid tubes. Inaccordance with the invention, the screen of each tube serves as anadditional control electrode. The control grid of each of these tubes isconnected to a corresponding multivibrator. The multivibrator 1G2 andits connection to the tube 112, as well as the screen grid connectionand the screen grid bias control for this tube, will be described indetail hereinafter. The other multivibrators and screen grid tubes allfunction in a some-- what similar manner.

The six multivibrators 102 to 107 are each supplied with two triggeringpulses. Conductor 122 is connected to the corresponding side of eachmultivibrator through a resistor. The conductor 122 is part of thecommon bias circuit for the multivibrators. The cathode of tube 126 isconnected to the common bias circuit between the conductor 122 and aterminal 128 (Fig. 5a) which is connected in any suitable manner (notshown) to a source of direct current bias of negative polarity. Theanode of the tube 126 is connected to the +13 terminal designated 164.The screen grid 131 of the tube 126 is connected to the previouslymentioned conductor 63 in which the signal pulses 43 and 44 appear. Theother set of triggering pulses is applied over the previously mentionedconnections 81 to 87. The code pulses and the pulses 69 when they areadditive, as shown in Fig. 4e trip the multivibrator in which they areadditive.

Three of the tubes 112, 113, and 114 are connected to draw plate currentthrough the horizontal deflection coil 134 (Fig. 5a) which is part ofthe yoke 21. The counterparts of these three tubes (not shown) exist inthe second portion ofthe code converterwhich lies to the right of thekinescope 12 in the schematic showingof Fig. a.

The remaining three tubes 115, 116, and 117 of the bank-of tubes 112 to117 are connected to draw plate current through the vertical deflectioncoils 139. A resistor 141 serves as a damping resistor for the yoke. Aresistor 143 also serves as a damping resistor.

A multivibrator 151 serves as a transfer sothat the bank ofmultivibrators 102 to 107, as well as the corresponding bank (not shown)to the right of kinescope 12, as shown in Fig. 5a, stores and recordselements of information, such as letters, alternately. The grids of themultivibrator 151 are connected through diodes 153 and 154 togroundpthrough a resistor 156. The cathode of the multivibrator tube 151is also connected to ground or to the circuit point to which theresistor 156 is returned. When the first pulse in a negative directionfrom the sync control device 68 is transmitted over the lead 81 throughthe condenser 158 to the diodes, the diode 15.3 or 154 will apply thisnegative pulse to the grid of the section of the multivibrator which isconducting.

Switch tubes 161 and 162 are provided and the condition of themultivibrator 151 determines which of these tubes is conducting. Thetubes 161 and 162 have similar circuit connections and therefore onlythe circuit connection of the tube 161 will be described. The circuitconnections for the tube 162 accomplish similar purposes for the portionof the equipment which lies to the right of the kinescope 12. The spacedischarge path of the tube 161 is connected between the +13 terminal 164and the negative bias terminal 128. Cathode resistors 168 and 169 areprovided which are in the form of multiple slider potentiometers.

Fig. 4c represents the voltage at the cathode 172 of the tube 161. It iseither equal to the negative bias applied at the terminal 128 when thetube 161 is cut off or rises to a value which is definitely fixed by theregulation of the grid circuit provided by a voltage regulator tube 174together with resistors 176 and 177. A diode rectifier 178 providesregulated direct current bias voltage for the grid 179 of the tube 161.

The screen grids of the tubes 112, 113 and 114 are connected to taps onthe multiple slider potentiometer 169. The screen grids of the tubes115, 116 and 117 are connected to the taps onthe multiple sliderpotentiometer 168. Voltage settings are arranged by the sliders on thepotentiometers 168 and 169 so that when the deflection tubes 112 to 117are conductive their screens are held to values which make the platecurrent have a ratio of 1-2-4. For example, if the tube 114 is set for.040 ampere, then the tube 113 is set for .020 ampere, and the tube 112is set for .010 ampere. With the plate current of the tubes 112, 113,and 114 set as stated, then the plate current of the tube 115 would beset for .010 ampere; the plate current of the tube 116 would be set for.020 ampere; and the plate current of the tube 117 would be set for .040ampere. The separate potentiometers'168 and 169 are provided tocompensate for differences in individual tubes.

The plate currents of the tubes 112, 113, and 114 combine in thedeflection coil 134 over the lead 135. Since these tubes are pentodes,the operation of one tube does not affect the operation of the other.Likewise, the plate currents of the tubes 115, 116, and 117 combinein'the coils 139 over the lead 140 to produce the vertical deflection.Coils 184 and 186 are additional deflection coils to generate thesmaller raster and are supplied from the raster generator 24 shown inFig. 3. It will be understood that the coils 184 and 186 may alsoinclude set values of direct current to establish the start position ofthe beam.

The operation will be clarified by taking a sequence of events. When thefirst start pulse, shown in Fig. 4b for example, reaches the synccontrol counting chain 68, it starts this counter and simultaneouslytrips the multivibrator 151 over lead 81 to the position where currentflows in its left branch, making the grid 179 of the tube 161 negative.The cathode 172 of this tube is also negative at this time. At thistime, the cathode 188 of the tube 162 goes positive. The cathode 188 isconnected by a conductor 191 to a condenser 193 and a rectifier 194 tothe grid connection for theleft-hand half of the multivibrator 107. Thepositive pulse appearing on conductor 191 at this instant resets themultivibrators 102 to 107 so that all have plate currents flowing in theleft branch. As a result of this, the tubes 112 to 117 are cut ofi sincetheir control grids are all at a negative potential because ofconductivity in the left branches of the multivibrators. These tubes arealso held at cut-off because all of their screen grids, supplied fromresistors 168 and 169 as explained above, are negative. In the sameswitching operation, the signal input tube 126 becomes active becausethe lead 191 goes positive and brings its signal grid 196 to its normalpotential. The connections to the grids 131 and 196 may be interchangedwhen the tube 126 is of the type, by now well known, in which both gridsare capable of exercising a control function.

As the first signal pulse comes into the tube 126 over the connection63, it raises somewhat the potential of all of the points connected tothe leads 82 to 87. Mid-way of the duration of the first signal pulse,the second timing pulse 69 shown in Fig. 4d arrives over lead 82 andtrips the multivibrator 102. Immediately, the control grid of the tube112 becomes slightly positive although this tube is still cut off by itsscreen. In the assumed example of Fig. 4a, it will be seen that thefirst letter N trips one more multivibrator 106. This leaves the controlgrids of the tubes 113, 114, 115, and 117 still negative.

As the second start pulse arrives, the multivibrator 151 goes over, thecathode 172 of the tube 161 goes positive, and the cathode 188 of thetube 162 goes negative. As a result, all of the screens of the tubes 112to 117 go to their normal positive voltage. The horizontal deflectioncurrent is set at .010 ampere, and the vertical deflection current isset at .020 ampere. This moves the beam in the cathode ray tube 12 tothe position N on Fig. 9. At the same time, the negative voltage in thelead 191 cuts off the tube 126 so that the deflection remainsundisturbed by incoming signals. Correspondingly, the voltage at thecathode 172 of the tube 161 operates a tube similar to the tube 126 (notshown) to the right of the cathode ray tube 12 as it appears in Fig. 5a.This occurs over the lead 198 which corresponds in function to the lead191. The screens of the tubes corresponding to the tubes 112 to 117, oneof which, 199, is shown, are cut ofi so that these tubes do notinterfere with the code already set up in tubes 112 to 117. Amultivibrator 201 is the first one of a series of multivibrators whichcorresponds to the multivibrators 102 to 107. Lead 198 resets thesemultivibrators through condenser 202 and rectifier 203.

Looking at Fig. 9, it will be seen that combinations of currents fromthree tubes in the ratio of l-2-4 can establish eight specificdeflections. The code of six units per letter of the illustrativeexample now under discussion, therefore, can select from 64 characters.It will be understood that one position could be used to call for ashift function. However, if 64 selections are sufiicient, it would notbe necessary in the arrangement described to incorporate a shiftfunction.

The letter advance unit 204 in Fig. 3 includes circuits to locate thehorizontal position of the small raster (shaded on Fig. 10) on the tube14. This letter advance unit may be any of the well-known electroniccounters such as that described in the Electronic Digital Countersarticle cited in the foregoing. The code converter 66 which has beendescribed in detail in connection with Figs. 5 and 5a of the drawingproduces a pulse on the lead 206 through rectifiers 208 and 209 as theraster finishes each letter. These pulses operate on the accumulatingcounter circuit of the letter advance unit 204 which constantly movesthe raster to the right so that a line of type is printed. This isaccomplished by boosting the horizontal deflection current in steps.This continues until a signal is received from the code selector 214 forthe carriage return function. The code selector 214 may be constructedeither as shown in Fig. 6 or Fig. 7 of the accompanying drawing. Thedisclosures of these figures will be described in more detail herein.The signal from the code selector discharges the accumulated horizontaldeflection set up by the counter 204 and starts over for the next line.At the same time, a signal going over to the paper advance control 34,which may be a magnetically-operated ratchet of any well known kind,moves the sensitized sheet 29 one line.

The code selector 214 (Figs. 3 and 5a) is required to identify a fewspecific code functions and from them to produce operating currents forapparatus functions other than character printing. Figs. 6 and 7 shownovel arrangements in accordance with the invention based on the use ofsaturation reactors sensitive to certain current valves rather thanvoltages. Referring to Fig. 6, two transformers 241 and 242 are shown.These transformers are connected in cascade and the primary of the firsttransformer is fed from an oscillator 240 which may generate alternatingcurrent at a frequency of, for example, 100 kc. Each transformer corestructure is saturable by a direct current winding. The transformer 241has a direct current winding 243 on its center leg, as well as thewinding 246 which carries horizontal deflection current. This windingalso appears in the schematic showing of Fig. 5a. The current in thewinding 243 is presettable, for example, by a rheostat 248.

The winding 246 carrying the deflection current is wound to oppose thewinding 243. Only when the two direct currents are equal will the corebe unsaturated andeffective. With special core material, the balancezone will be very sharply defined. The transformer 242 also has twowindings 251 and 252 on its center leg. These windings function in thesame manner as the windings 243 and 246. In the arrangement of Fig. 6just described, there will be no current output to a device to becontrolled unless both deflection currents are at preselected values. Afull Wave bridge-type rectifier 255 rectifies the output from theoscillator so that it is available at terminals 256 for application toapparatus which is to be controlled. In the illustrative arrangement,the output is shown as operatingthe paper advance control 34. Condensers257 and 258 will short circuit the alternating current from theoscillator 240 and block the alternating current flux from the centerlegs when the cores are unsaturated.

Fig. 7 shows an arrangement which is similar to Fig. 6 except that thesaturable cores 261 and 262 are used as variable inductances in serieswith a 100 kc. source 264, a resistor 266, and a condenser 268. A secondcondenser 271 is set to tune the two inductances represented by thecoils on the core structures 261 and 262 to parallel resonance at theoutput frequency of the generator 264 when the cores are unsaturated.Coils 276 and 277 correspond with the coils 246 and 251 of Fig. 6. Coils278 and 279 provide for direct current saturation. The condenser 268tunes the system to series resonance when the cores are saturated andthe inductance a minimum. This tuning accentuates the sharpness ofcontrol. The output signal is rectified by a bridge rectifier 281. Theoutput is opposite to that of Fig. 6 since minimum current flows at theterminals 282 when controlled apparatus is to operate.

Fig. 9 suggests some of the controls which might be required and whichcould be provided by employing control arrangements such as areillustrated in Figs. 6 and 7. The functional operations to be providedare rest or space position, line advance, carriage return and messagestart. One reactor-selector combination would be needed to. make eachselection. All control coils could be in series With the deflectioncircuits. The currents in the deflectioncircuits indicate thecoordinates of the displacement of the beam in the tube.

Fig. 8 of the drawing indicates a modified receiver for the codedsignals. Similar pieces of equipment will be given similar referencecharacters to those previously used except that the suffix "a will beadded. The control units are similar to those of Fig. 3 butthe twoflying spot systems and the raster generator have been replaced by aspecial tube.

The special tube is designated in its entirety by reference character291. The pattern of characters shown by Fig. 9 is projected from a slide293 onto a photocathode 296 which is semi-transparent in the preferredform of the tube. The deflection control, which is set up in the codeconverter 66a for selecting the desired letter, sweeps the electronimage emitted from the photocathode 296 across a barrier 298 until onlythe image of the chosen letter falls on an aperture 299. The electronimage from the photocathode is focussed by a focusing coil 301 anddeflection is provided by a yoke shown conventionally at 302. The imageof the selected letter passing through the aperture 299 is refocussed ona fluorescent screen 304 with the aid of a focussing coil .306.Deflection currents supplied to a deflecting yoke unit 308 from theletter advance unit 204a place the luminous image of the selectedcharacter in the desired position on the screen. The remainder of thesystem of Fig. 8 is the same as that already described in detail withreference to Fig. 3 of the drawings. As indicated on Fig. 8, the tube291 is provided with a plurality of focussing and acceleratingelectrodes shown illustratively in the form of rings.

Fig. ll of the drawings discloses another embodiment of a receiver forthe coded signals which is similar to that shown by Fig. 8. A tube 321is employed which is identical to 291 of Fig. 8. The pieces of equipmentwhich are similar to those discussed in connection with Fig. 3 of thedrawings are given the same reference characters with the suffix badded. The code selector 214b includes an additional selector circuitwhich actuates a message advance device 324 when a complete message orsection of selected typescript of a complete message has been received.The code selector 214b, in addition to stepping the position of thescanning raster to provide the letter spacing function, also includes aline advance mechanism so that a counter in the letter and line advancemechanisms 326 will step the raster vertically by a distance of oneline. The system of Fig. 11, which operates in accordance with theinvention, is preferable when recording at high speeds. For example, at6,000 words per minute or words per second, the line by line paperadvance would occur at about 10 per second. This would be about themaximum for a step-wise movement of a paper web. By recording a numberof lines before a paper movement occurs, the frequency of mechanicaladvance of the paper will be considerably reduced.

In all of the embodiments where a speed of 10,000 words per minute, forexample, is to be recorded, the continuous movement of the paper webwould be desirable. This can be provided if the type line on the face304 of tube 291 is slightly skewed and correction voltages are set up inthe control units for type lines less than full length. It should benoted that the screen 304 need not retain the image of an entire line ormessage because each successive letter will expose the photographicpaper substantially immediately. High actinic value for the emittedlight is required rather than a persistent image in the phosphor.

What is claimed is:

l. A system for the electronic selection of indicia comprising cathoderay beam apparatus, a plurality of indicia producing means operativelyassociated with said cathode ray beam apparatus, means in said cathoderay beam apparatus. for producing a plurality of cathode ray beams, eachsuch beam-having a cross-section characteristic of one of said indicia,fixed means to select one of said beams, means responsive to receivedcoded signals for producing beam defiectien in said apparatusselectively along a plurality of deflection coordinates whereby saidcathode ray beams in said apparatus are displaced to effect selection ofa single indicia by said fixed means, a second beam deflection means fordeflecting a selected beam, and means whereby said second deflectionmeans is operable along a single coordinate of deflection in response torepeated operations of said first-named beam deflection means.

2. A system for the electronic selection of indicia comprising a radiantenergy source, a cathode ray tube having means on the inner surface of atube face for producing an electron stream in response to radiant energyexcitation, means for maintaining the cross-sectional area of saidstream, deflection means for deflecting said cathode ray stream, meansassociated with the outer face of said tube having characters to beselected applied thereon, said last-named means being in the radiantenergy path between said tube face and said radiant energy source,control means operative to control said deflection for deflecting thecathode ray stream of said tube in one coordinate direction, and afurther control means operative to control said deflection fordeflecting the cathode ray stream of said tube in another coordinatedirection.

3. A system for the electronic selection of indicia comprising a radiantenergy source, a cathode ray tube having means on the inner surface of atube face for producing an electron stream in response to radiant energyexcitation, means for maintaining the cross-sectional area of saidstream, deflection means for deflecting said cathode ray stream, meansassociated with the outer face of said tube having characters to beselected applied thereon, said last-named means being in the radiantenergy path between said tube face and said radiant energy source,control means operative to control said deflection for deflecting thecathode ray stream of said tube in one coordinate direction, a furthercontrol means operative to control said deflection for deflecting thecathode ray stream of said tube in another coordinate direction, anapertured mask in the path of said electron stream, said aperturepassing a portion of said stream as a cathode ray beam whosecross-section represents a selected character, means for maintainingthecross-sectional area of said beam, a second tube face, means on theinner surface of said second tube face for providing radiant energy inresponse to impingement of said beam, and means for deflecting said beamin one direction.

4. A system for the electronic selection of indicia comprising a radiantenergy source, a cathode ray tube having means on the inner surface of atube face for producing an electron stream in response to radiant-energy excitation, means for maintaining the crosssectional area ofsaid stream, deflection means for deflecting said cathode ray stream,means associated with the outer face of said tube having characters tobe selected applied thereon, said last-named means being in the radiantenergy path between said tube face and said radiant energy source,control means operative to control said deflection for deflecting thecathode ray stream of said tube in one coordinate direction, a furthercontrol means operative to control said deflection for deflecting thecathode ray stream of said tube in another coordinate direction, anapertured mask in the path of said electron stream, said aperturepassing a portion of said stream as a cathode ray beam whosecross-section represents a selected character, means for maintaining thecrosssectional area of said beam, a second tube face, means on the innersurface of said second tube face for providing radiant energy inresponse to impingement of said beam, means for deflecting said beam inone direction, and means for deflecting said beam in a coordinatedirection.

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